Va mutin (1983b)




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VA Mutin (1983b)
[ Species diversity and ecology of hoverflies (Diptera, Syrphidae) visiting some flowers of the Lower Amur region ]
pp 100-109 in RG Soboleva (ed) Obzor otdel'nykh otryadov nasekomykh Dal'nego Vostoka [Systematics and ecological-faunistic review of insect Orders in the Far East], Academy of Sciences of USSR, Vladivostok, USSR
Introduction

(literature)


Material & Methods

The study was done in Primorye during 1976-1980 and 1979 in and around Komsomolsk in Khabarovski Krai. Samples were taken of the syrphid visitors to the following flowers:

Goat Willow Salix caprea L.

** willow Salix xerophila Floder

Kingcup Caltha membranacea Schipz.

Eastern Strawberry Fragaria orientalis Losinsk.

** Rose Rosa acicularis Lindl.

Daurian Rosa Rosa davurica Pall.

** Sorbaria sorbifolia (L.) A.Br.

Amur Angelica Angelica amurensis Schischk.

** Senecio cannabifolius Less.

** Hieracium umbellatum L.


Flies were taken only on flowers during one hour with 30-minute intervals between. Temperature, RH and wind speed were measured every hour, and general weather conditions notes. The total number of flies collected was about 4000. To identify the species, I used the authenticated collections of the Zoological Institute of the Academy of Sciences. Identification of Cheilosia were done by Barkalov.
Peculiarities of the species diversity of syrphids in the Lower Amur.

Recorded 174 species in 60 genera. (listed)


Characteristics of anthophile complexes of syrphids for some plants

Salix caprea: Melangyna was dominant

Salix xerophila: Parasyrphus, Psilota, Cheilosia, Eristalis subdominant.

Caltha: 22 spp. Cheilosia dominant with 40-55% of individuals. Seasonal changes (Table 2)

Only on this flower: Platycheirus immarginatus, P.ovalis, Melanostoma dubium,



Sphegina clunipes, Sphegina eoa, Sphegina spheginea, Lejota ruficornis,

Helleniola nigra, Chalcosyrphus jacobsoni

Fragaria: 42 spp of 23 genera, dominant Cheilosia with max in June. Subdominants of

Chalcosyrphus, Xylota and Eristalis

Rosa acicularis 50 spp of 30 genera. Dominant Pipiza, subdominants Xyloat 21.8%, Criorhina (6.8%)

and Temnostoma (5%)



Rosa davurica 32 spp in 17 genera. Dominant Xylota (75%), subdominant Pipiza (16.7%)

Sorbaria 44 spp in 24 genera. Dominant Eristalis (34.6%), subdominants Sphegina (16%),

Temnostoma (14.8%) and Xylota (13.6%).

Angelica 22 spp in 14 genera. Dominant Cheilosia (87.4%), subdominant Eristalis (7.9%)

Senecio 17 spp in 11 genera. Dominant Eristalis (44-74%), subdominants Sphaerophoria

(11.8 and 9%), Syrphus (4.7 and 6.5%) and Episyrphus (15.6 and 22.9%).



Hieracium 10 spp in 6 genera. Dominant Eristalis (56.2%), subdominants Sphaerophoria indiana

(21.9%) and Episyrphus balteatus (10.9%)

Overall dominant were spp in the genus Eristalis: E.nemorum, E.rossicus and E.cerealis.

Phenology and seasonal changes of the number of syrphids

The activity period of hoverflies in Lower Amur conditions is 5-5.5 months, from the 3rd decade of April to the beginning of October. At the end of April the first syrphids appear, mainly from Melangyna, that actively visit: Adonis amurensis Rgl & Radde and Anemone amurensis Kom . From the beginning of flowering of willow during the first decade of May, the number of syrphids increases greatly, due to the appearance of Episyrphus balteatus, Scaeva lapponica, Criorhina sichotana, etc. At the beginning of 2nd decade of May, the diversity of species reaches more than 30 spp from 20 genera, and at the end of the same decade there are about 70 spp. The number of individuals increases simultaneously. For example, on 13 May 1979 during one hour in the period of high activity, about 25 individuals on average were found, but on 20 May more than 50 individuals. At the end of May, many individuals of Sphegina, Neoascia, Lejota, Brachyopa and Parasyrphus appear. At the beginning of June there is a peak of numbers (Fig 1). Spp from Blera, Pocota, Mallota, Ceriana and Temnostoma appear. Especially many flies can be found during the first half of June on Fragaria, Rosa acicularis, Spiraea. For instance during one hour on the flowers of Rosa acicularis on 8 June 1979, we found 80 individuals on average.

During the second half of June, the number of flies decreases due to several factors. The end of the flight of late-spring and early summer species, especially of Episyrphus balteatus, Syrphus vitripennis, S.ribesii, Sphaerophoria indiana, etc., that have several generations, and also because of the low number of flowering plants with open flowers. During the period between flowering of Rosa davurica and Sorbaria sorbifolia, the number of syrphids is low.

During the second half of July there is a second peak in numbers, due to the mass flight of Cheilosia, Sphaerophoria, Syrphus, Eristalis and the start of the appearance of late-summer species: Paragus tibialis, Betasyrphus serarius, Asacrina porcina, Eumerus strigatus, Eumerus tuberculatus, Volucella pellucens, V.inanis, Spilomyia maxima, etc. Massive flight of these species can be seen until the second decade of August. Then there is a sharp decrease, and in September hoverflies are low in number, about 10 indidivuals per hour. A few individuals can still be found until the first decade of Sept. Sometimes in the end of Sept, species of Syrphinae make a swarm at some places near the roads, river banks and in open places in the forest.

Therefore the seasonal pattern has two maxima to it.
Activity of hoverflies during the day

Fig 2: Daily activity of syrphids on (a) Salix caprea (b) Rosa acicularis (c) Sorbaria sorbifolia

1 = numbers of hoverflies per hour; 2 = air temperature (C); 3 = relative humidity (%)


Conclusions

1. There are very many syrphids in this region. In the relatively small territory where this study took place, we found 174 species from 60 genera. 14 species were found for the first time for the Far East. The syrphid diversity has a boreal character: 17% are Palaearctic.

2. Each plant studied can be characterized by its own complex of syrphids, with specific dominants and subdominants. There are significant quantitative and qualitative differences among plants, between plants with a long flowering period and plants growing in different conditions. The diversity of syrphids are closer for plants growing in the same biotope and flowering at the same time.

3. The flight period of syrphids in the Lower Amur is 5.5 months. During this period there are three phenological groups: spring, early summer and late summer groups. The number of syrphids has two maxima: the first at the end of May - beginning of June, and the second at the end of July.

4. Diurnal activity of syrphids depends mainly on weather conditions, especially on temperature and light conditions.The period of activity is usualy 10-12 hours, and the period of flower visiting is about 6-8 hours. Maximal number of syrphids on flowers is detected in spring and late autumn during the second half of the day, from 1500 - 1800 hours, and during the summer period from 1100 - 1400 hours.

5. About 38% of species of syrphids are entomophagous in the larval stage. The highest number of flies on flowering plants is in the middle of May - beginning of June, and in August. These flies intensively visit many entomophilic plants, and therefore these plants can be used to attract predatory syrphids.


translated Denis Tikhonov

3.5.2000


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